It is previously known to irrigate crops in large fields using either a center pivot or a linear move irrigation device. Originally, these devices had a spaced-apart array of individual sprinklers provided atop a main water supply line that was elevated above a field. Over time, U-shaped horseshoe adapters were added in order to allow attachment of downwardly extending drops made from rigid water lines to which a sprinkler was affixed at a bottom end. However, for crops that grow to relatively tall heights, such as corn, there existed a need to adjust the height of sprinklers.
As shown in FIG. 1, rigid water lines of prior systems were replaced on a center pivot irrigation device 10 with flexible hoses 23 that affixed between the horseshoe 22 and the sprinkler head 36 (see FIG. 2) to form a flexible drop 18. Center pivot irrigation device 10 has a main line, or water pipe 20 that receives a supply of water at a center stand 13 and extends out to a terminal end 16, delivering water to sprinkler/regulator assemblies 36 on a serial array of spans 14 that are each supported between adjacent towers 12 by a pair of wheels 15. A sprinkler weight 30 is provided adjacent each sprinkler/regulator assembly 36 in order to reduce movement of drop 23 due to wind. As crops grow in elevation, the hose 23 is wrapped around the main waterline pipe 20, as shown in FIG. 2, in order to raise the sprinkler head of sprinkler/regulator assembly 36. A worker 11 manipulates each hose about pipe 20 by walking along truss rods 27, which are suspended by adjacent bowstring truss assemblies 21 of the truss 19. Worker 11 also wraps a drop weight 30 and sprinkler/regulator assembly 36 about pipe 20 as hose 23 is wrapped about pipe 20. However, worker 11 can slip and fall from truss rods 27 on the device 10 and be injured when raising and lowering such a sprinkler/regulator assembly 36. Accordingly, a need exists to adjust height of sprinklers on a moving irrigation device 10 without placing a worker 11 at risk of injury from a fall.